1. Field of the Invention
This invention describes a lubricant system for polyvinylchloride resins, articles made from polyvinylchloride and a method of extrusion utilizing the lubricants with polyvinylchloride.
2. Description of the Art Practices
In my earlier U.S. Pat. No. 4,425,458, issued Jan. 10, 1984, I described the use of polyguerbet alcohol esters as lubricants for polycarbonate resin compositions. Similarly, in U.S. Pat. No. 4,487,874, issued Dec. 11, 1984, I disclose polycarbonate lubricants which were formed from the partial esterification of pentaerythritol with an aliphatic carboxylic acid followed by the reaction with an aliphatic dicarboxylic acid.
In my earlier U.S. Pat. No. 4,336,176, issued Jun. 22, 1982, I disclose the manufacture of polyvinylchloride compounds containing an organo-tin compound and a partial ester having functionality as both an internal lubricant and as a co-stabilizer of the resin.
U.S. Pat. No. 4,690,977 to Hosoi et al, issued Sep. 1, 1987, describes vinylchloride polymers comprising a grafted copolymer, the vinylchloride polymer, a rubber copolymer, and a lubrication system which includes a wax lubricant and epoxidized soybean oil. Hosoi et al makes similar disclosures in U.S. Pat. No. 4,645,795, issued Feb. 24, 1987.
U.S. Pat. No. 4,797,440 to Schofield et al, issued Jan. 10, 1989, describes a thermoplastic polymeric organic medium in the presence of a lubricant and a processing additive containing a divalent aliphatic radical. Among the thermoplastic polymers disclosed by Schofield et al, are polyvinylchloride. The possible materials utilized as lubricants by Schofield et al include 12-hydroxy stearic acid, stearic acid, stearamide, a polyethylene wax, as well as zinc and calcium stearates.
The stabilization of polyvinylchloride is taught in U.S. Pat. No. 4,338,226, issued Jul. 6, 1982, to Worschech et al. Various calcium and zinc fatty acids and polyol partial esters are disclosed. It is also disclosed by Worschech et al that high molecular weight complex esters may be utilized as lubricants and as well natural fats.
The stabilization of vinylchloride polymers is taught by Crochemore et al in U.S. Pat. No. 4,102,839, issued Jul. 25, 1978. The use of epoxydized soybean oil, a wax, calcium stearate and zinc stearate is disclosed by Crochemore for the processing of vinylchloride.
U.S. Pat. No. 3,951,883, issued Apr. 20, 1976, to Ruchlak, et al, discloses polyvinylchloride molding compositions. Tenaka et al, in U.S. Pat. No. 4,072,657, issued Feb. 7, 1978, discloses synthetic resins which include among others, vinylchloride-vinylacetate copolymers, and described as plasticizers therefore, fatty oils, and waxes.
U.S. Pat. No. 4,392,581, issued Jul. 12, 1983 to Itsubo et al describes vinylchloride resin compositions obtained from a mixed fatty acid ester of glycerin. U.S. Pat. No. 3,578,621 issued May 11, 1971 to Stapfer describes stearamide waxes which may be utilized for plastic processing.
The present invention deals with a simple lubricant additive system for polyvinylchloride resins which is superior to amide wax lubricant systems and which does not present the negatives of epoxidized soy systems. Advantages are also seen in Brabender fusion time, and reduction of frictional heat build up while lowering extrusion die pressure.
Throughout the specification and claims percentages and ratios are by weight, temperatures are in degrees Celsius, and pressures are in KPa gauge unless otherwise indicated. To the extent that any of the references cited herein are applicable, they are hereby specifically incorporated by reference. Ranges and ratios given herein may be combined.